← actarefs.com
Duke NetID
Protocol Overview

Indications: hypotension/shock, respiratory failure. Phased array probe, cardiac mode. Left lateral decubitus when feasible.

7 required views PLAX ×2 · PSAX ×1 · A4C ×1 · SC4C ×1 · IVC ×2
PLAX — Parasternal Long Axis ▼
View 1 — PLAX "Deep" Shot (depth ≥18 cm)
  • Purpose: Evaluate for left pleural effusion posterior to the descending thoracic aorta
  • Increase depth to ≥18 cm to visualize far field beyond the heart
  • Critical distinction: Pleural effusion = anechoic collection posterior to descending aorta; pericardial effusion tracks anterior to descending aorta
Do not miss a left pleural effusion by using shallow depth only
View 2 — PLAX "Shallow" Shot (depth just beyond thoracic aorta)
  • Probe: Left sternal border, 3rd–4th ICS, marker → right shoulder
  • 2D: RV (anterior), IVS, LV cavity, MV leaflets, LVOT, AV, aortic root, LA, descending aorta (posterior)
  • Assess: LV size and systolic function (visual EF), RV size, MV and AV leaflet motion, pericardial effusion
  • M-mode at MV tips: EPSS — >7 mm suggests reduced EF
  • Zoom LVOT: measure diameter (inner edge to inner edge, mid-systole) for stroke volume
PSAX — Parasternal Short Axis ▼
View 3 — PSAX at Papillary Muscle Level
  • From PLAX: rotate 90° clockwise, marker → left shoulder
  • 2D: circular LV with anterolateral and posteromedial papillary muscles
  • Assess: RWMA (all coronary territories represented at this level), LV systolic function (fractional area change)
  • D-sign / septal flattening: flattening in diastole → RV volume overload; in systole → RV pressure overload
  • Fan superiorly → AV level (morphology, RVOT); fan inferiorly → apex (apical wall motion)
Best single view for RV pressure vs volume overload All coronary territories visible at papillary muscle level
Apical ▼
View 4 — Apical 4-Chamber (A4C)
  • Probe: cardiac apex (5th ICS, midaxillary line or PMI), marker → 4–5 o'clock; left lateral decubitus ideal
  • 2D: LV (left of screen), RV (right), LA, RA, MV, TV, IAS, IVS
  • Ensure LV is not foreshortened — apex should taper to an ellipsoid, not appear rounded
  • Assess: LV systolic function (visual EF), RV:LV ratio (>0.6 = dilated; >1.0 = severely dilated), RWMA, pericardial effusion
  • M-mode at lateral TV annulus: TAPSE (≥17 mm)
  • M-mode at lateral MV annulus: MAPSE (≥10 mm)
Subcostal ▼
View 5 — Subcostal 4-Chamber (SC4C)
  • Probe: subxiphoid, nearly flat; marker → patient's left (3 o'clock); patient supine, knees bent
  • Liver as acoustic window; RV nearest transducer
  • Best view for pericardial effusion — fluid between myocardium and pericardium, distinct from liver and pleural fluid
  • Assess: global biventricular function, interatrial septum
  • Backup when parasternal/apical windows poor (COPD, MV, surgical dressings, post-sternotomy)
View 6 — IVC Long Axis
  • From SC4C: rotate 90° CCW, marker → patient's head (12 o'clock), angle slightly rightward
  • Landmark: hepatic vein confluence entering IVC near RA
  • Measure IVC diameter ~2 cm from RA junction
  • Assess collapsibility (spontaneous breathing) or distensibility (mechanically ventilated)
  • IVC >50% collapse → RAP ~3 mmHg; IVC >2.1 cm + <50% collapse → RAP ~15 mmHg
  • ⚠ Multiple confounders limit interpretation — see Reference tab for full caveat list
Interpret with caution post-bypass and in right heart failure
View 7 — IVC Short Axis
  • From IVC long axis: rotate 90° — IVC in cross-section as it enters RA
  • Confirms IVC vs aorta; assess for thrombus in IVC lumen
  • Round, non-pulsatile IVC vs oval, pulsatile aorta
Lung Ultrasound — Duke ICU 6-Zone Protocol (L1–L3, R1–R3) ▼
Protocol Overview ▼
Protocol Overview

6 required zones, bilateral. Label clips with zone code. Probe: linear (superficial) or curvilinear (effusion, deeper structures).

6 required views (L1, L2, L3, R1, R2, R3) Linear probe — sliding, A/B-lines Curvilinear — effusion, consolidation
Left Hemithorax ▼
L1 — Left Anterior Lung Zone ▼
L1 — Left Anterior Lung Zone
  • Probe: mid-clavicular line, 1st–3rd ICS
  • Assess: lung sliding (present/absent), A-lines, B-lines
  • Absent sliding here → start tracking for lung point (pneumothorax)
L2 — Left Lateral Lung Zone ▼
L2 — Left Lateral Lung Zone
  • Probe: anterior axillary line, 3rd–5th ICS
  • Assess: lung sliding, A-lines, B-lines
  • Search for lung point if pneumothorax suspected
L3 — Left Posterolateral Lung Zone ▼
L3 — Left Posterolateral Lung Zone
  • Probe: mid-to-posterior axillary line, 5th–7th ICS
  • Assess: pleural effusion, consolidation, atelectasis
  • >90% sensitivity for pleural effusion at posterolateral zone
Right Hemithorax ▼
R1 — Right Anterior Lung Zone ▼
R1 — Right Anterior Lung Zone
  • Probe: mid-clavicular line, 1st–3rd ICS
  • Assess: lung sliding, A-lines, B-lines (same as L1)
R2 — Right Lateral Lung Zone ▼
R2 — Right Lateral Lung Zone
  • Probe: anterior axillary line, 3rd–5th ICS
  • Assess: same as R1; search for lung point if pneumothorax suspected
R3 — Right Posterolateral Lung Zone ▼
R3 — Right Posterolateral Lung Zone
  • Probe: mid-to-posterior axillary line, 5th–7th ICS
  • Assess: pleural effusion, consolidation, atelectasis (same as L3)
Key Findings — Interpretation Summary ▼
Pattern Recognition ▼
Pattern Recognition
  • Lung sliding present + A-lines → normal aeration (or COPD/asthma with air trapping)
  • B-lines (≥3 per field, bilateral) → interstitial syndrome (pulmonary edema, ARDS, interstitial pneumonia)
  • Absent lung sliding + A-lines + lung point → pneumothorax (lung point is pathognomonic)
  • Consolidation → tissue-like pattern ± air bronchograms; dynamic air bronchograms = pneumonia; static = atelectasis
  • Pleural effusion → anechoic dependent collection; assess for septations (complex/exudative effusion)
  • Seashore sign (M-mode) → normal sliding; barcode/stratosphere sign → no sliding → pneumothorax
Bilateral B-lines → pulmonary edema Unilateral B-lines → pneumonia, atelectasis, contusion Absent sliding + A-lines → rule out PTX before attributing to other cause
Post-Cardiac Surgery Considerations ▼
Post-Cardiac Surgery Considerations
  • Left pleural effusions common post-CPB — often identified at L3; most common indication for drainage in CTICU
  • B-lines post-bypass: may represent pulmonary edema, TACO, or atelectasis — correlate with clinical context
  • Subcutaneous air post-sternotomy can interfere with anterior zones (L1, R1) — lateral and posterior zones (L2/L3, R2/R3) usually more reliable
  • Pericardial vs pleural effusion (PLAX deep shot): fluid posterior to descending aorta = pleural; anterior to descending aorta = pericardial
FAST & Renal-GU — Duke ICU Protocol (5 Required Views) ▼
Protocol Overview ▼
Protocol Overview

Indications: shock, respiratory failure, trauma. Curvilinear probe. Lung views (eFAST extension) use linear or curvilinear probe.

5 required views Label "RUQ" vs "LUQ" — spleen and liver can look similar
View 1 — Right Upper Quadrant (RUQ) / Morrison's Pouch ▼
View 1 — Right Upper Quadrant (RUQ) / Morrison's Pouch
  • Probe: right flank, coronal plane (marker cephalad), probe between rib interspaces
  • Visualize: hepatorenal recess (Morrison's pouch), right diaphragm, right pleural space
  • Fan through: assess for free fluid between liver and kidney, hemothorax above diaphragm
  • Free fluid: anechoic collection in hepatorenal space; even a thin sliver = significant volume
  • Label: "RUQ"
Most sensitive abdominal region — free fluid detected here first in supine patients
Views 2 & 3 — Left Upper Quadrant (LUQ) / Splenorenal ×2 ▼
Views 2 & 3 — Left Upper Quadrant (LUQ) / Splenorenal ×2
  • Probe: left posterior flank, more posterior than RUQ; probe between rib interspaces, marker cephalad
  • Visualize: splenorenal recess, left diaphragm, left pleural space
  • Fan through: free fluid between spleen and kidney, left hemothorax
  • Obtain 2 clips (standard protocol) to ensure adequate coverage
  • Label: "LUQ"
Left side is harder — probe must be more posterior and superior than RUQ
Views 4 & 5 — Pelvis / Bladder ×2 ▼
Views 4 & 5 — Pelvis / Bladder ×2
  • Probe: suprapubic, marker toward patient's right for transverse view; rotate 90° for sagittal
  • Bladder as acoustic window (fill with fluid if empty for better visualization)
  • Transverse: assess for free fluid lateral to bladder, in pouch of Douglas (females) or rectovesical pouch (males)
  • Sagittal: posterior to bladder in dependent pelvis
  • Obtain both transverse and sagittal clips
eFAST Extension — Bilateral Anterior Lung Views ▼
eFAST Extension — Bilateral Anterior Lung Views
  • Anterior chest, 2nd ICS midclavicular line bilaterally
  • Pneumothorax: absent lung sliding + absent B-lines + A-lines present → lung point confirms
  • Hemothorax: anechoic collection above diaphragm in RUQ/LUQ views (fan superiorly)
Positive FAST + hemodynamic instability → OR Sensitivity 69–98%; negative does not exclude injury; serial exams increase yield
Post-Sternotomy Limitations ▼
Post-Sternotomy Limitations
  • Pericardial effusion post-cardiac surgery often loculated — subcostal alone may miss posterior/lateral collections
  • Drains and pacing wires create artifact — correlate with drain output and clinical exam
  • Hemothorax post-sternotomy: differentiate from effusion by echogenicity and clinical context (drain output, Hct)
  • Abdominal free fluid in cardiac surgical patients: consider hepatic congestion (RA hypertension), ascites, or abdominal compartment complications
Lower Extremity Venous Compression — Duke ICU Protocol (5+1 Points per Leg) ▼
Protocol Overview ▼
Protocol Overview

Linear high-frequency probe. 5 required compression sites per leg, 1 optional. Compress in transverse plane — normal vein collapses completely; thrombosed vein does not. Record each site with and without compression.

10 required views (5 per leg) +2 optional (adductor canal ×2) Label laterality at minimum ("LEFT" / "RIGHT")
Femoral Region (bilateral) ▼
Point 1 — Common Femoral Vein (CFV) ▼
Point 1 — Common Femoral Vein (CFV)
  • Probe transverse at inguinal ligament
  • Identify CFV (medial) and CFA (lateral)
  • Compress: complete collapse = normal; non-compressible = DVT
Label: L CFV / R CFV
Point 2 — CFV at Greater Saphenous Vein (GSV) Junction ▼
Point 2 — CFV at Greater Saphenous Vein (GSV) Junction
  • Slide probe slightly distally to saphenofemoral junction
  • Identify GSV entering CFV — "Mickey Mouse sign": CFV, CFA, and GSV visible in transverse
  • Compress at this level
Label: L GSV / R GSV
Point 3 — CFV at Lateral Perforator Vein ▼
Point 3 — CFV at Lateral Perforator Vein
  • Continue distally; identify lateral perforator vein entering CFV
  • Can be difficult to visualize but usually obtainable
  • Compress at this level
Label: L perf / R perf
Point 4 — Femoral Vein (FV) — Mid-Thigh ▼
Point 4 — Femoral Vein (FV) — Mid-Thigh
  • Continue distally into mid-thigh; FV runs deep to sartorius muscle alongside the SFA
  • Previously called "superficial femoral vein" — misnomer, it is a deep vein
  • This is the segment missed by 2-point protocols; SRU recommends compression here to avoid false negatives
  • Compress at this level
Label: L FV / R FV Most commonly missed segment in 2-point protocols
Popliteal Region (bilateral) ▼
Point 5 — Popliteal Vein ▼
Point 5 — Popliteal Vein
  • Patient: knee slightly flexed (pillow under knee or frog-leg position)
  • Probe transverse in popliteal fossa
  • Identify popliteal vein (superficial) and popliteal artery (deep, pulsatile)
  • Compress; fan through to trifurcation of calf veins
Label: L pop / R pop
Optional ▼
Point 6 — Adductor Canal (Optional) ▼
Point 6 — Adductor Canal (Optional)
  • Probe transverse at distal medial thigh
  • FV within adductor canal (between sartorius and adductor muscles)
  • Compress at this level
  • Perform when clinical suspicion is high despite negative proximal exam
Calf vein assessment: defer to formal duplex in vascular lab
Technique & Interpretation ▼
Technique & Interpretation
  • Normal: vein fully compressible with direct transducer pressure in transverse plane
  • DVT: non-compressible lumen — partial or complete; echogenic thrombus may be visible
  • Augmentation (Doppler): squeeze distal calf — increased venous flow; absence suggests proximal obstruction
  • Negative exam but ongoing suspicion: complete duplex Doppler (vascular lab) within 5–7 days
High relevance post-cardiac surgery — HIT, femoral cannulation sites, prolonged immobility
Gastric Protocol ▼
Gastric POCUS — Duke ICU Protocol (2 Required Views)
Protocol Overview ▼
Protocol Overview

Indication: aspiration risk assessment. Low-frequency curvilinear probe. Sagittal epigastric plane. Landmark: gastric antrum between left lobe of liver (anterior) and pancreas/aorta (posterior).

2 required views — supine + RLD Curvilinear probe, 2–5 MHz
View 1 — Supine Sagittal ▼
View 1 — Supine Sagittal
  • Probe sagittal at epigastrium; liver (anterior) and aorta/pancreas (posterior) as landmarks
  • Identify gastric antrum in cross-section
  • Assess qualitatively: empty, fluid, or solid content
  • Fluid appears anechoic/hypoechoic; solid content is heterogeneous, hyperechoic ("frosted glass")
View 2 — Right Lateral Decubitus (RLD) Sagittal ▼
View 2 — Right Lateral Decubitus (RLD) Sagittal
  • Roll patient to right side and repeat sagittal epigastric view
  • Most sensitive position — gastric contents pool in dependent antrum
  • Measure antral cross-sectional area (CSA) at the level of the aorta
  • CSA = π × (AP × CC) / 4 (ellipse formula; AP and CC diameters measured in cm)
RLD is the primary quantitative view — always obtain this position
Interpretation
3-Point Grading System ▼
3-Point Grading System
  • Grade 0 (empty): No fluid in either position → low aspiration risk
  • Grade 1: Fluid visible in RLD only → consistent with baseline secretions, low risk
  • Grade 2: Distended antrum with fluid in both supine and RLD → gastric volume >100 mL, higher aspiration risk

Solid content (heterogeneous, hyperechoic "frosted glass") → high risk regardless of grade or volume.

Quantitative Volume — Perlas Formula ▼
Quantitative Volume — Perlas Formula
  • Gastric volume (mL) = 27.0 + 14.6 × RLD CSA − 1.28 × age
  • Volume >1.5 mL/kg → full stomach (high aspiration risk)
  • Volume >100 mL → correlates with Grade 2; consider RSI or case deferral
  • Coronal view (optional): may improve detection of gastric distension
>1.5 mL/kg = full stomach threshold Source: ASRA gastric POCUS recommendations (Haskins 2021, 2025)
Cardiac Surgery Applications ▼
Cardiac Surgery Applications
  • Urgent/emergent cases with uncertain NPO status: cardiogenic shock, STEMI, type A dissection
  • Decision support before reintubation in the CTICU (failed extubation, respiratory distress)
  • Post-cardiac arrest resuscitation prior to securing airway
  • Delayed gastric emptying: opioid infusions, prolonged ICU stay, diabetic gastroparesis
Minimum Exam Requirements (every CCE)
  • Visualize LV and RV in a minimum of 2 views per chamber
  • Quantify at least one of: LV stroke volume, RVSP, or diastolic function grade
  • Visualize mitral, tricuspid, and aortic valves with both 2D and color Doppler

If a view cannot be obtained, document the attempt. Workflow at each window: 2D → Color Doppler → Spectral Doppler.

★ = overlaps with basic FoCUS *** = optional / clinically indicated only
Parasternal Long Axis PLAX ★ Basic ▼
Parasternal Long Axis — RV Inflow PLAX-RVI *** Optional ▼
Parasternal Short Axis PSAX ★ Basic (papillary level) ▼
Apical 4-Chamber A4C ★ Basic ▼
Apical 5-Chamber A5C ▼
Apical 2-Chamber A2C ▼
Apical 3-Chamber (Apical Long Axis) A3C / APLAX *** Optional ▼
Subcostal 4-Chamber SC4C ★ Basic ▼
Subcostal IVC SC-IVC ★ Basic ▼
Key Hemodynamic Parameters — Quick Reference ▼
ParameterWindow / MethodNormal / Threshold
LVOT VTIA5C — PW Doppler18–22 cm; stroke distance for trending
Stroke VolumeA5C — LVOT VTI × LVOT area60–100 mL
E/e′ (average)A4C — TDI at MV annulus<14 normal; ≥14 → elevated filling pressures
TAPSEA4C — M-mode at TV annulus≥17 mm (normal RV longitudinal function)
RV s′A4C — TDI at TV annulus≥10 cm/s (normal RV systolic function)
RVSPA4C — CW through TR jet4(TR Vmax)² + RAP; >35 mmHg elevated
IVC diameterSC-IVC — 2 cm from RA≤2.1 cm + >50% collapse → RAP ~0–5 mmHg; ⚠ multiple confounders — see Reference tab
EPSSPLAX — M-mode at MV tips≤7 mm normal; >7 mm → reduced EF
MAPSEA4C — M-mode at MV annulus≥10 mm (normal LV longitudinal function)
PAATPSAX (AV level) — PW at PV>100 ms normal; <60 ms → severe PH
Dimensionless indexA5C — LVOT VTI / AV VTI>0.50 normal; <0.25 → severe AS
Cardiac ▼
Pericardial Effusion / Cardiac Tamponade ▼
  1. 1
    Anechoic space between epicardium and pericardium — circumferential in large effusions. Key distinction: pericardial fluid tracks anterior to descending aorta on PLAX; pleural fluid tracks posterior
  2. 2
    RV diastolic collapse — most specific echocardiographic sign of tamponade; best seen in PLAX or subcostal views
  3. 3
    RA systolic inversion — RA wall inverts inward during ventricular systole; duration >1/3 of cardiac cycle is both sensitive and highly specific
  4. 4
    Respiratory variation in MV/TV inflow — trans-mitral variation >25–30%, trans-tricuspid >40–60% on PW Doppler; echocardiographic pulsus paradoxus
  5. 5
    Plethoric IVC — diameter >2.1 cm with <50% inspiratory collapse; reflects elevated RAP from impaired venous return
⚠ Post-cardiac surgery: Effusions occur in ~18% post-op and are frequently loculated hematomas. A loculated hematoma can cause regional tamponade compressing only selected chambers (often left-sided) — classic RV collapse, RA inversion, and Doppler variation are often absent. TTE may be inadequate — TEE is often required for posterior or left-sided hematomas not visible on standard windows. Always compare with pre-op and intraoperative imaging. Distinguish pre-existing epicardial fat pad (echogenic, anterior, non-dependent, present on prior studies) from new hematoma (heterogeneous, may be posterior or lateral, new since prior imaging).
RV Failure ▼
  1. 1
    RV dilation — RV:LV ratio >1.0 in A4C (RV-focused view); RV basal diameter >4.1 cm indicates dilation
  2. 2
    Reduced TAPSE — M-mode at lateral TV annulus in A4C; <17 mm indicates RV longitudinal systolic dysfunction
  3. 3
    Interventricular septal flattening (D-sign) — diastolic flattening = RV volume overload; systolic flattening = RV pressure overload; eccentricity index >1.0 = RV overload at PSAX papillary level
  4. 4
    Reduced RV S' velocity — TDI at lateral TV annulus; <10 cm/s indicates RV systolic dysfunction
  5. 5
    Reduced RVFAC — fractional area change <35% in A4C; trace RV endocardium in diastole and systole
TAPSE:PASP ratio <0.32 mm/mmHg = RV-PA uncoupling McConnell's sign → free wall akinesis + apical sparing = acute PE until proven otherwise
LV Failure / Low EF ▼
  1. 1
    Visual EF estimation — qualitative "eyeball" in PLAX, PSAX, A4C, A2C; experienced operators achieve κ >0.9 vs formal biplane Simpson's; classify as <30%, 30–50%, >50%
  2. 2
    EPSS >7 mm — E-point septal separation on PLAX M-mode at MV tips; >7 mm sensitive for LVEF ≤30%; >12–17 mm = moderate-to-severe dysfunction
  3. 3
    MAPSE <10 mm — mitral annular plane systolic excursion; M-mode at lateral MV annulus in A4C; reflects reduced LV longitudinal function
  4. 4
    Regional wall motion abnormalities (RWMA) — akinesis, hypokinesis, or dyskinesis; PSAX papillary level covers all coronary territories; suggests ischemic etiology
  5. 5
    LV dilation — LVEDD >5.6 cm on PLAX, or visually enlarged LV cavity; often accompanies chronic systolic dysfunction
Hypovolemia / Fluid Responsiveness ▼
  1. 1
    Small, hyperdynamic IVC — diameter <2.1 cm with >50% inspiratory collapse in spontaneously breathing patients; suggests low RAP and potential volume responsiveness
  2. 2
    IVC collapsibility index (cIVC) — spontaneous breathing: cIVC ≥48% predicts FR with 84% sensitivity, 90% specificity; MV: dIVC >15% separates responders from non-responders
  3. 3
    Small, hyperdynamic LV ("kissing walls") — near-obliteration of LV cavity in systole on PSAX or A4C; small LVEDA; suggests severe hypovolemia and reduced preload
  4. 4
    LVOT VTI variation with passive leg raise (PLR) — >10–12% increase in LVOT VTI after PLR predicts fluid responsiveness; applicable in spontaneous breathing, MV, and arrhythmias
  5. 5
    Flat, collapsed IVC — IVC diameter <9 mm at multiple levels suggests significant hypovolemia; highly predictive when combined with hyperdynamic LV
⚠ Critical caveat: IVC reflects right-sided filling pressures, not LV preload or fluid responsiveness directly. RV dysfunction, elevated IAP, MV settings, and patient effort all confound IVC dynamics. PLR + LVOT VTI change is the most robust dynamic predictor. See Reference tab for full IVC caveat list.
Venous Congestion — VExUS ▼
  1. 1
    Plethoric IVC (>2.0 cm) — gating criterion; if non-plethoric, VExUS grade = 0 regardless of other findings
  2. 2
    Hepatic vein Doppler — normal: biphasic S > D; mild: S = D; severe: systolic flow reversal (S wave reversed)
  3. 3
    Portal vein pulsatility — normal: continuous low-pulsatility; mild: pulsatility index >30%; severe: pulsatility >50% with intermittent flow reversal
  4. 4
    Intrarenal venous Doppler — normal: continuous flow; mild: discontinuous biphasic (S and D); severe: monophasic diastolic-only flow
  5. 5
    VExUS grading — Grade 0: IVC <2 cm; Grade 1: plethoric + no severe; Grade 2: plethoric + 1 severe; Grade 3: plethoric + ≥2 severe → highest congestion, associated with AKI and adverse outcomes
Integrates IVC + hepatic + portal + renal vein Doppler Curvilinear probe for all VExUS views
Aortic Stenosis (POCUS Screening) ▼
  1. 1
    Calcified / thickened AV with restricted opening — PLAX and PSAX (AV level); heavily calcified, immobile leaflets are the hallmark 2D finding
  2. 2
    Elevated peak aortic jet velocity (Vmax) — CW Doppler from A5C or A3C; Vmax ≥4 m/s = severe; 3–4 m/s = moderate (2020 ACC/AHA VHD guidelines)
  3. 3
    Elevated mean transvalvular gradient — from CW Doppler envelope; ≥40 mmHg = severe AS
  4. 4
    Reduced AVA by continuity equation — LVOT VTI × LVOT area / AV VTI; AVA ≤1.0 cm² = severe; AVAi ≤0.6 cm²/m² = severe indexed
  5. 5
    Concentric LV hypertrophy — increased wall thickness, normal/small cavity; secondary sign of chronic pressure overload
⚠ POCUS caveat: Sensitivity ~83%, specificity ~100% for significant AS by experienced operators. CW Doppler alignment critical — misalignment underestimates gradients. Low-flow, low-gradient AS requires dobutamine stress echo or CT-AVC — not diagnosable by POCUS.
Pulmonary ▼
Pneumothorax ▼
  1. 1
    Absent lung sliding — most sensitive sign; visceral pleura no longer glides against parietal pleura; also absent in pleurodesis, mainstem intubation, apnea, severe consolidation
  2. 2
    Absent B-lines — a single B-line at any intercostal space rules out pneumothorax at that location; B-lines require pleural apposition
  3. 3
    Lung point — transition where sliding appears and disappears with respiration; 100% specific for pneumothorax; marks its border
  4. 4
    Barcode / stratosphere sign (M-mode) — parallel horizontal lines replacing the normal seashore sign; confirms absent lung sliding
  5. 5
    Absent lung pulse — in apnea, cardiac pulsations transmitted to pleura ("lung pulse") normally visible; absence suggests PTX rather than other causes of absent sliding
Sensitivity 89%, specificity 99% — far exceeds supine CXR (30–75%) Start at 2nd ICS MCL anteriorly; look for lung point laterally
Pleural Effusion ▼
  1. 1
    Anechoic space above diaphragm — gravity-dependent collection between pleural layers; best in posterolateral zones (L3/R3) with patient upright or semi-recumbent
  2. 2
    Quad sign — effusion bounded by pleural line (superior), lung line (inferior), and rib shadows (lateral) forming a quadrilateral
  3. 3
    Sinusoid sign (M-mode) — lung line moves toward pleural line with inspiration; distinguishes effusion from consolidation
  4. 4
    Spine sign — vertebral bodies visible above the diaphragm through the effusion (normally blocked by air-filled lung)
  5. 5
    Fluid characterization — simple (anechoic) vs. complex (echogenic, septated, floating debris); complex = exudate, empyema, or hemothorax
>90% sensitivity — far exceeds supine CXR Post-CPB: left effusions common — always check L3 on post-op exam
Pulmonary Embolism (Indirect Signs) ▼
  1. 1
    RV dilation (RV:LV >1.0) — A4C view; most commonly used echocardiographic marker of PE-related RV strain (2026 AHA/ACC PE Guideline)
  2. 2
    McConnell's sign — akinesia of RV mid-free wall with preserved (hypercontractile) apical motion; distinctive for acute PE
  3. 3
    60/60 sign — RVOT acceleration time <60 ms + notching of RVOT Doppler envelope + TR gradient <60 mmHg; consistent with acute RV pressure overload from PE
  4. 4
    Reduced TAPSE — reflects acute RV systolic impairment; guides risk stratification per 2026 AHA/ACC PE guideline
  5. 5
    Paradoxical septal motion + plethoric IVC — leftward septal bowing in systole + non-collapsing IVC; combination strongly suggests hemodynamically significant PE
Thrombus-in-transit (RA/RV/PA): rare, pathognomonic, emergent BLUE protocol for PE: A-line profile + positive DVT compression US
Interstitial Lung Syndrome (B-line Pattern) ▼
  1. 1
    ≥3 B-lines per intercostal space — vertical hyperechoic artifacts from pleural line to screen bottom, moving with sliding; ≥3 in a single field = "positive" zone
  2. 2
    Bilateral diffuse B-lines (B-profile) + preserved sliding — symmetric anterior/lateral distribution = acute cardiogenic pulmonary edema (most common cause)
  3. 3
    B-lines + reduced/absent sliding (B'-profile) — suggests non-cardiogenic disease: ARDS, viral pneumonitis, interstitial lung fibrosis
  4. 4
    Irregular / thickened pleural line — fragmented pleural line, subpleural irregularities = pneumonia, ARDS, or ILD rather than cardiogenic edema
  5. 5
    Quantification and distribution — total B-line count correlates with extravascular lung water; focal/asymmetric = pneumonia or contusion; monitor response to diuresis serially
Non-Cardiac / Abdominal ▼
Abdominal Free Fluid (FAST) ▼
  1. 1
    Anechoic stripe in Morrison's pouch — hepatorenal recess; most sensitive location for free fluid in the supine patient
  2. 2
    Fluid in splenorenal recess or perisplenic space — LUQ view; probe must be more posterior and superior than RUQ
  3. 3
    Pelvic free fluid — rectovesical pouch (males) or pouch of Douglas (females); transverse and sagittal suprapubic views
  4. 4
    Subdiaphragmatic fluid — fluid above liver or spleen, below diaphragm; fan superiorly from RUQ/LUQ views
  5. 5
    Serial exams increase sensitivity — sensitivity 69–98% for hemoperitoneum; serial exams improve yield to 72–93%
Positive + hemodynamic instability → OR Negative does not exclude injury
Deep Vein Thrombosis (DVT) ▼
  1. 1
    Non-compressible vein — hallmark finding; normal vein collapses completely with transducer pressure in transverse plane; thrombosed vein does not
  2. 2
    Echogenic intraluminal material — visible thrombus; acute thrombus may be anechoic and detectable only by non-compressibility
  3. 3
    Distended vein — acutely thrombosed veins are often larger than the adjacent artery
  4. 4
    Absent or diminished color flow — on color Doppler, flow absent or reduced in thrombosed segment
  5. 5
    Absent augmentation — distal calf compression fails to augment proximal flow on spectral Doppler
Post-cardiac surgery: HIT, femoral cannulation, immobility — high pretest probability Duke protocol: 5+1 compression points per leg
Lung Consolidation / Pneumonia ▼
  1. 1
    Tissue-like sign ("hepatization") — consolidated lung resembles liver parenchyma in echogenicity
  2. 2
    Air bronchograms — hyperechoic linear/punctate structures within consolidation; dynamic (moving with respiration) = pneumonia; static = atelectasis
  3. 3
    Shred sign — irregular, jagged border between consolidated and aerated lung
  4. 4
    Fluid bronchograms — anechoic fluid-filled bronchi within consolidation; suggests obstructive atelectasis
  5. 5
    Associated pleural effusion — parapneumonic effusion common with bacterial consolidation; characterize for septations or empyema features
Protocol3 ▼
View Count Summary ▼
ExamRequiredOptionalNotes
Focused Cardiac7—PLAX ×2, PSAX ×1, A4C ×1, SC4C ×1, IVC long ×1, IVC short ×1
Lung6—L1, L2, L3, R1, R2, R3 — label every clip
FAST / Renal-GU5—RUQ, LUQ ×2, Pelvis ×2 — label RUQ vs LUQ
LE Venous DVT1025 per leg (CFV, GSV, perf, FV, pop) + adductor canal optional
Gastric21Supine sagittal + RLD sagittal; coronal optional
Total303
Probe Selection ▼
ProbeFrequencyUse For
Phased array2–5 MHzCardiac (all views), subcostal IVC
Linear5–12 MHzLung sliding / A-B lines, DVT compression, superficial structures
Curvilinear2–5 MHzFAST (abdomen/pelvis), lung effusion/consolidation, gastric, aorta
Clip Labeling Guide ▼
  • Cardiac: PLAX-deep, PLAX, PSAX, A4C, SC4C, IVC-long, IVC-short
  • Lung: L1, L2, L3, R1, R2, R3
  • FAST: RUQ, LUQ (label — spleen and liver look similar), Pelvis-transverse, Pelvis-sagittal
  • DVT (left leg): L CFV, L GSV, L perf, L FV, L pop — use R prefix for right leg
  • Gastric: Gastric-supine, Gastric-RLD
Cardiac4 ▼
CCE — Key Hemodynamic Parameters ▼
ParameterWindow / MethodNormal / Threshold
LVOT VTIA5C — PW Doppler18–22 cm; use for trending SV
Stroke VolumeLVOT VTI × π/4 × (LVOT diameter)²60–100 mL
E/e′ (average)A4C — TDI lateral + medial MV annulus<14 normal; ≥14 → elevated filling pressures
TAPSEA4C — M-mode at TV annulus≥17 mm
MAPSEA4C — M-mode at MV annulus≥10 mm
RV s′A4C — TDI at TV annulus≥10 cm/s
RVSPA4C — CW through TR jet4(TR Vmax)² + RAP; >35 mmHg elevated
EPSSPLAX — M-mode at MV tips≤7 mm normal; >7 mm → reduced EF
PAATPSAX (AV level) — PW at PV>100 ms normal; <60 ms → severe PH
Dimensionless indexA5C — LVOT VTI / AV VTI>0.50 normal; <0.25 → severe AS
RV:LV ratioA4C — area ratio<0.6 normal; >1.0 severely dilated
LV Function — Quick Assessment ▼
MethodViewFinding
Visual EFAny<30% / 30–50% / >50% — bucket estimation
EPSSPLAX M-mode>7 mm → reduced EF
Fractional area changePSAX papillary level<35% → systolic dysfunction
MAPSEA4C M-mode<10 mm → reduced longitudinal function
Biplane Simpson'sA4C + A2CTrace endocardium ED and ES
Pericardial vs Pleural Effusion ▼
  • PLAX deep shot (≥18 cm depth): fluid posterior to descending aorta = pleural; fluid anterior = pericardial
  • SC4C: best view for pericardial effusion — fluid between myocardium and pericardium, distinct from liver
  • Post-cardiac surgery: effusions often loculated — do not rely on subcostal alone; check multiple windows
  • Tamponade signs: RA diastolic collapse, RV diastolic collapse, IVC plethora (>2.1 cm, non-collapsing), respiratory variation in inflow velocities
D-Sign — RV Overload Interpretation ▼
TimingMechanismCause
Systolic flatteningRV pressure overloadPE, pulmonary hypertension, ARDS, hypoxic vasoconstriction
Diastolic flatteningRV volume overloadTR, ASD, RV infarct, post-CPB RV dilation
Both systole + diastoleCombinedSevere RV failure
IVC3 ▼
RAP Thresholds ▼
IVC DiameterCollapsibility (cIVC)Estimated RAPInterpretation
≤2.1 cm>50%0–5 mmHgLow RAP
≤2.1 cm<50%~8 mmHgIntermediate — use clinical context
>2.1 cm<50%10–20 mmHgElevated RAP
Source: ASE/EACVI (Lang 2015). Moderate correlation with CVP only — interpret in context.
10 Conditions Where IVC POCUS May Fail ▼
IVC Is Not a Stand-Alone Measure

IVC diameter reflects a complex interplay of volaemia, right heart function, intrathoracic pressure, and intra-abdominal pressure simultaneously. Only extreme cIVC values (>40–50%) carry predictive value. Post-CPB: unreliable in first 6 hours (Sobczyk 2015, 2016). Always integrate with cardiac function and lung POCUS.

  • 1. High PEEP / low tidal volume MV — low respiratory variation despite fluid responsiveness (false negative)
  • 2. Assisted ventilation / NIV / CPAP — unpredictable interplay; IVC variation unreliable (FP and FN)
  • 3. Variable spontaneous breathing — deep breaths exaggerate cIVC (FP); shallow breaths reduce sensitivity (FN)
  • 4. Asthma / COPD exacerbation — auto-PEEP dilates IVC; forced expiration can mimic collapse (FP and FN)
  • 5. Chronic RV dysfunction / severe TR — chronically dilated IVC; FR may coexist (FN)
  • 6. RV myocardial infarction — dilated IVC + venous congestion may coexist with FR (FN)
  • 7. Cardiac tamponade — IVC plethora expected; fluid challenge may still be beneficial (FN)
  • 8. Intra-abdominal hypertension — compresses IVC regardless of volaemia; blunts variation (FP and FN)
  • 9. Local mechanical factors — ECMO cannulae, cava filters, IVC thrombosis, extrinsic compression
  • 10. Lateral IVC displacement — M-mode plane migrates off-axis; overestimates cIVC (FP) — use short-axis to confirm
All 10 are prevalent in the cardiac surgical ICU Via G et al. ICM 2016; Di Nicolò P et al. JCM 2023; Millington SJ. CJA 2019
Lung1 ▼
Pattern Recognition ▼
PatternDiagnosis
Sliding + A-linesNormal aeration (or COPD/asthma)
Bilateral B-lines (≥3/field)Interstitial syndrome — pulmonary edema, ARDS, ILD
Unilateral B-linesPneumonia, atelectasis, contusion
No sliding + A-linesPneumothorax — confirm with lung point
Lung pointPathognomonic for pneumothorax
Consolidation ± air bronchogramsPneumonia (dynamic) or atelectasis (static)
Anechoic dependent collectionPleural effusion — assess for septations
M-mode seashore signNormal lung sliding
M-mode barcode/stratosphere signAbsent sliding → pneumothorax
Gastric1 ▼
Aspiration Risk Quick Reference ▼
GradeFindingRisk
Grade 0No fluid in either positionLow
Grade 1Fluid in RLD onlyLow — baseline secretions
Grade 2Fluid in both supine + RLDHigher — volume >100 mL; consider RSI
Solid contentHeterogeneous / "frosted glass"High regardless of grade
Perlas formula: Volume (mL) = 27.0 + 14.6 × RLD CSA − 1.28 × age · CSA = π × (AP × CC) / 4 · >1.5 mL/kg = full stomach